Vitamin D and B12, should GLP-1 users get checked?

Two vitamin levels come up for people on a GLP-1, and two published sources name them specifically.

Vitamin D

WebMD points to the one most often named: "Vitamin D is the most common deficiency linked to GLP-1 drugs." The wording is "linked to", which is an association. Do not read it as proof that the drug caused your level to drop.

B12

MDedge gives a reason to test: "It is beneficial for patients to get blood work periodically to check on B12 status, because insufficient B12 can contribute to the fatigue patients experience while on the medication." The cause and effect is concrete: when the B12 level runs low, fatigue can follow, so tiredness on a GLP-1 might not be the drug alone.

Routine versus worth a call

MDedge treats fatigue as something patients experience on the medication, so some tiredness is routine. Tiredness that does not lift is worth raising with your provider, with B12 as one thing to ask about.

Background reading

MedlinePlus Medical Encyclopedia carries a page on health screenings for men ages 18 to 39. For the wider context on weight, see the MedlinePlus obesity page and the Cleveland Clinic page on weight control and obesity. Tirzepatide users can also read the MedlinePlus drug information on tirzepatide injection.

Is blood work in your plan

Ask whether blood work for vitamin D and B12 is part of your plan, and how often it will be repeated. If the answer is no, ask why not.